diff --git a/morph/grid/local/README.rst b/morph/grid/local/README.rst
index 2297816d2e5c2faddb8b889a850d2e97ee0475c9..ddccc67def0596516284b7a71189b2a50105ee38 100644
--- a/morph/grid/local/README.rst
+++ b/morph/grid/local/README.rst
@@ -38,7 +38,7 @@ Use the local development environment
 
 Build and start the VMs::
 
-  vagrant up
+  VAGRANT_DEFAULT_PROVIDER=virtualbox vagrant up
 
 Then::